PLANT MANUFACTURE OF FOOD 



131 



All of the sugars have numerous characteristics in common, 

 such as sweetness, solubility in water, and readily yielded energy 

 when oxidized. They are found dissolved in the cells, and can be 

 easily transported from one part of the plant to another. The 

 presence of abundant amounts of sugars in plants is often 

 associated with low temperatures; sugars aid in the maintenance 

 of sufficient osmotic pressure within the cells to keep the proteins 



STARCHES 



GUMS 



CELLULOSE 



DEXTR/NS 



DOUBLE SUGARS 



(SUCROSe - /MALTOSE) 



FATS 



Fig. 82. — ^From glucose, plants elaborate numerous other carbohydrate foods 



as well as fats. 



from being precipitated by freezing. Cool weather, for example, 

 speeds up the transfer and storage of sugar in the sugar beet 

 roots; cool autumns are essential for good sugar beet areas. 

 Arctic plants have been found to contain relatively higher 

 percentages of sugar than temperate species. And it has been 

 recently demonstrated that feeding plants sugar makes them 

 more resistant to low temperatures. 



A common carbohydrate derived from glucose is starch 

 (GeHioOs)!!, which is insoluble in water and therefore is not a 

 form of energy-food capable of transportation from one part of 



